docs: def get_eid_rlz(self, monitor=None):
          """
          :returns: a composite array with the associations eid->rlz
          """
          eid_rlz = []
          for rup in self.rup_array:
              ebr = EBRupture(mock.Mock(serial=rup['serial']), rup['srcidx'],
                              self.grp_id, rup['n_occ'], self.samples)
              for rlz, eids in ebr.get_eids_by_rlz(self.rlzs_by_gsim).items():
                  for eid in eids:
                      eid_rlz.append((eid, rlz))
          return numpy.array(eid_rlz, [('eid', U64), ('rlz', U16)])